<h2>Problem 79</h2>
<div style="color:#666;font-size:80%;">17 September 2004</div><br />
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<p>A common security method used for online banking is to ask the user for three random characters from a passcode. For example, if the passcode was 531278, they may ask for the 2nd, 3rd, and 5th characters; the expected reply would be: 317.</p>
<p>The text file, <a href='project/keylog.txt'>keylog.txt</a>, contains fifty successful login attempts.</p>
<p>Given that the three characters are always asked for in order, analyse the file so as to determine the shortest possible secret passcode of unknown length.</p>

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